Reports shed light on Great Lakes water levels

Rising and falling water levels in the Great Lakes are influenced by evaporation, rain and snowfall in ways that aren't fully understood and are becoming less predictable as the climate warms, according to scientific reports made public Tuesday.
AP Wire
Jan 22, 2014

This winter's bitterly cold weather is forming ice on areas of the lakes that will reduce evaporation by blocking water vapor from rising into the atmosphere and keeping water temperatures cool well into summer. That should help water levels continue a rebound that began in 2013 following an unusually long slump across most of the lakes dating from the late 1990s, said John Lenters, senior scientist at LimnoTech, an environmental consulting firm in Ann Arbor.

But recent studies show that evaporation and ice cover regulate lake levels in more complex ways than previously believed, according to a new paper published by the Great Lakes Integrated Sciences and Assessments Center, a joint U.S.-Canadian research team led by Lenters. The team is developing a network to measure evaporation rates continuously, providing data that will improve water level forecasts — a helpful tool for the cargo shipping and tourism industries and others whose livelihoods are affected by the inland seas' ups and downs.

Meanwhile, another paper being released this week says the Great Lakes have ebbed and flowed on a fairly consistent 10-year cycle for much of the past century, although the steep decline that began in 1998 suggests the pattern may have been broken. That study, led by Carl Watras of the Wisconsin Department of Natural Resources, says the fluctuations have been influenced by atmospheric trends hatched as far away as the northern Pacific Ocean.

Taken together, the studies confirm that climate is by far the biggest player in determining water levels, Watras said. Human actions make little difference, despite noisy debates over whether structures should be built to regulate flows between lakes or whether communities outside the watershed should be permitted to draw from them, he said.

"The two big factors are precipitation and evaporation," said Watras, who is also a research fellow with the University of Wisconsin's Center for Limnology, whose paper is being published this week in the journal Geophysical Research Letters. "The question looking ahead is how they will behave as the climate evolves. Will we get more of both? Or will one begin to dominate?"

Rainfall and runoff from melting snow have helped compensate for water lost to evaporation over the years. But winter ice cover has shrunk dramatically in recent decades, removing an important restraint on evaporation.

Unless precipitation keeps pace, "it's pretty darn clear that rising regional temperatures will increase evaporation and ... the lake levels are going to decline," said Don Scavia, director of the Graham Sustainability Institute at the University of Michigan, which oversees the Lenters-led research project.

Great Lakes levels fluctuate seasonally, rising during wet springs and dropping in the fall. They also go through longer-term high and low periods. Although most of the lakes are hundreds of feet deep far from shore, changes in water levels make a big difference in shallower areas such as shorelines and busy shipping channels.

Lenters' team kicked off the first coordinated effort to calculate year-round evaporation rates on the lakes in 1998, establishing five stations across the region where measurements are taken.

Their studies have shown that even though ice cover during cold winters limits evaporation, the benefit is partially offset by heavy evaporation in the weeks before the ice forms as the water rapidly cools, the paper says. Yet heavy ice can keep the water colder for longer than usual and delay the onset of the high-evaporation season.

Such nuances illustrate the importance of expanding the evaporation monitoring network, said Drew Gonewold, a hydrologist with the National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory. It provides data for six-month lake level forecasts produced by the U.S. Army Corps of Engineers.

"In order to understand what's driving water levels and correctly respond when water levels get low, we need to know really well the relative impact of precipitation and evaporation," Gronewold said.

For the Wisconsin study, Watras and colleagues used data from inland lakes as well as the Great Lakes to link water level changes to atmospheric patterns similar to the jet stream that originate over the Pacific. Those air flows regulate the influx of moist air from the Gulf of Mexico into the Great Lakes region, influencing rainfall during warm-weather months that can replenish water lost to evaporation.

The study showed that shifts in the air patterns correlated with ups and downs in the Great Lakes that happened over roughly decade-long periods until the most recent drop-off that began in 1998 and may only now be ending, Watras said.

It's too soon to say whether the roughly 10-year pattern has ended, or whether the recent low-water period will prove to be a "hiccup" that temporarily interrupted it, he said. But climate change may be ushering in a time of lengthier and more pronounced rises and falls.

"Something's happening now that has not happened in the past, as far as we know," he said.

 

Comments

Lanivan

"But climate change may be ushering in a time of lengthier and more pronounced rises and falls".

There is simply no question but that Earth is in the midst of climate change, with record amounts of carbon being injected into the atmosphere; the degree and rate of Arctic ice melting is the highest in 3 million years; Earth has experienced 345 months in a row of above normal global temperatures. 2012 was the globally warmest year in recorded history; Weather systems are stalling or becoming slower, resulting in a great number and more intense weather patterns.

In fact, the Earth's ice is melting much faster than even the computer models predicted.

Climate change/global warming, and the changes it brings in not only our oceans, but our fresh bodies of water, must be addressed. Our forefathers did just that - they recognized the challenge, had the vision to see the future for our children and grandchildren that would be affected by that challenge, and acted.

Teddy Roosevelt recognized the importance of keeping some land from the hands of developers, and instituted the first ever national park system. Nixon started the EPA, George H.W. Bush signed the Clean Air Act, and let us not forget Reagan's words in his State of the Union address of 1984:

"And as we develop the frontier of space, let us remember our responsibility to preserve our older resources here on Earth. [Preservation of our environment is not a liberal or conservative challenge, it's common sense] - italics mine.

Though this is a time of budget constraints, I have requested for EPA one of the largest percentage budget increases of any agency. We will begin the long, necessary effort to clean up a productive recreational area and a special national resource—the Chesapeake Bay.

To reduce the threat posed by abandoned hazardous waste dumps, EPA will spend $410 million. And I will request a supplemental increase of 50 million. And because the Superfund law expires in 1985, I've asked Bill Ruckelshaus to develop a proposal for its extension so there'll be additional time to complete this important task.

On the question of acid rain, which concerns people in many areas of the United States and Canada, I'm proposing a research program that doubles our current funding. And we'll take additional action to restore our lakes and develop new technology to reduce pollution that causes acid rain.

We have greatly improved the conditions of our natural resources. We'll ask the Congress for $157 million beginning in 1985 to acquire new park and conservation lands. The Department of the Interior will encourage careful, selective exploration and production on our vital resources in an Exclusive Economic Zone within the 200-mile limit off our coasts—but with strict adherence to environmental laws and with fuller State and public participation".

watchingyou

I do not for one second buy into the Global Warming idea. I do believe that we can do a lot better in the way our environment is treated and we should all do our part to make it better. That is why I firmly believe in killing and digesting carbon creating tasty animals and saving as much oxygen creating plant life as possible. But for all of you that believe that all of our Ice caps will melt off and never return, I will hug a tree for you when I get home. :)

bigdeal

why does it not surprise me you are goofing off at work on the computer?

watchingyou

Goofing off? Is it any of your business what or where I do anything? Are you stalking me? How about sticking to friendly debate or joshing around.

LessThanAmused

Hey, at least he's not threatening your life!

watchingyou

It's not hard to track IP's LTA. It would not be wise to get that worked up over this stuff enough to make any threats.

LessThanAmused

I agree, yet some people do...I refer you to one of the share your photo threads from just like week or so....

bigdeal

wow! didn't read this post for a day and it explodes! Just having fun with you watchingyou. I wouldn't know how to stalk someone, nor would I want to. I have a life, it takes a lot of my time. Sorry for the late reply...

bigdeal

your last sentence triggered my work comment btw, "when I get home I'll hug a tree for you", around noon time. Just figuring you were goofing off at work. Guess I hit a nerve with something close to the truth. My bad & your really bad apparently. Glad I missed your unedited comments below, as I gave up trying to be more civil in 2014.

watchingyou

Naah just called you a stalker and said you were infatuated with me. I figured you were messing around, I just had a knee jerk reaction. You know me, I try not to be too serious.

watchingyou

Edited due to inappropriate name calling. Need to be nice. Now Bigdeal, since you are obviously bored and are so interested in me I give you full permission to display my first name.

Lanivan

In other words, you are covering your bases just in case the "idea" of global warming doesn't pan out. Don't worry about GHTrib stalkers - you have about 98% of the scientific community that has spent decades on research based on "science", not "ideas" or "opinions", that would like to disagree with you that their findings are more than just "ideas".

watchingyou

Exactly, decades of research of weather on a planet that is millions of years old. I understand and admitted that we don't treat the planet as well as we should but I don't believe for a minute in Global Warming. If humans were the sole reason for the Greeenhouse Effect on earth then why is the same thing happening on Venus? Has anyone looked at the Solar Cycles? I am just saying that I don't buy it all. Some may be real but some is pure diplomatic propaganda.

Vladtheimp

Crickets to my request - let me help.

So where did that famous “consensus” claim that “98% of all scientists believe in global warming” come from? It originated from an endlessly reported 2009 American Geophysical Union (AGU) survey consisting of an intentionally brief two-minute, two question online survey sent to 10,257 earth scientists by two researchers at the University of Illinois. Of the about 3.000 who responded, 82% answered “yes” to the second question, which like the first, most people I know would also have agreed with.

Then of those, only a small subset, just 77 who had been successful in getting more than half of their papers recently accepted by peer-reviewed climate science journals, were considered in their survey statistic. That “98% all scientists” referred to a laughably puny number of 75 of those 77 who answered “yes”. http://www.forbes.com/sites/larr...

Proud of your factoid now?

Lanivan

Sorry, Vlad - I am now just sitting down and seeing your request for a link.

There are many links I could provide that address my "factoid", but I'm into the Skeptical Sciene website, as we know that scientists are always skeptical until they can prove otherwise. And what's really neat is that you can select the degree of complexity of explanation. Also, check out the column on the left hand side, "Most used climate myths".

"Scientists need to back up their opinions with research and data that survive the peer-review process. A Skeptical Science peer-reviewed survey of all (over 12,000) peer-reviewed abstracts on the subject 'global climate change' and 'global warming' published between 1991 and 2011 (Cook et al. 2013) found that over 97% of the papers taking a position on the subject agreed with the consensus position that humans are causing global warming. In a second phase of the project, the scientist authors were emailed and rated over 2,000 of their own papers. Once again, over 97% of the papers taking a position on the cause of global warming agreed that humans are causing it".

http://www.skepticalscience.com/...

This isn't a matter of pride versus prejudice!

Vladtheimp

And here's some input from real life http://wattsupwiththat.com/2013/...

Best comment regarding the hiding of scientific data by Cook:

Engaging these people has become too draining. They arise, zombielike with their old-hat guesswork, regurgitated myths and claims of consensus, all the while throwing insults at any who disagree with their smug surety.

Lanivan

Ok - you don't like SkepticScience? No problem. Here's one from NASA.....

"Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities,1and most of the leading scientific organizations worldwide have issued public statements endorsing this position. The following is a partial list of these organizations, along with links to their published statements and a selection of related resources".

http://climate.nasa.gov/scientif...

OR:

This year Powell found that out of 2,258 peer-reviewed articles on climate change – authored by 9,136 scientists in the period between November 2012 and December 2013 – just ONE denied the existence of man-made climate change. http://ampp3d.mirror.co.uk/2014/...

Like I said, there's vast quantities of articles out there just like these. Guess they are all just a bunch of smug, zombielike, tiresome, mythological figures.

Yep. Confuse, Divide, and Delay....just like clockwork.

Vladtheimp

Thanks - I will try to verify but it may not be easy due to the odious history of Global Warming scammers fudging history, statistics, studies, and credentials.

Some, like the Powell article, set up strawmen (only 1 article out of 2,228); I'm not aware of any reasonable person that denies the earth has warmed - we just came out of the "Little Ice Age" in the 1800's; I don't know of any reasonable person who denies man has not had some impact on the environment - that would be plain foolish. I also don't know of any reasonable person who doesn't recognize there has been no statistically significant warming over the last 15 years, regardless of the increased amounts of carbon man has placed into the atmosphere. That said, there is no basis to conclude that the calamitous predictions of the zealots that have caused untold trillions to be extracted from the global economy are anywhere near accurate - we know they have been proven inaccurate - or that man is the principal cause of the changes in the climate, which are cyclical.

Rational people recall being lectured incessantly by the scammers that one cannot take a localized weather event to disprove Global Warming. Then, when the temperature doesn't increase for the past 15 years, we are treated to lectures that localized events, Hurricane Sandy, forest fires set by man, prolonged cold snaps, drought, and snow storms are now evidence of "Global" Warming. And the effort is intensified to "Hide the Decline." As the claims get more shrill and contradictory, reasonable people are starting to question the whole premise, and the huge amounts spent to counteract it.

Lanivan

As I said, you are a skeptic - and one who has the benefit of remembrances of past hysteria over decades to influence your opinion. So be it. But I leave you with the fact that, as of 2014, Global Warming/Climate Change has attained the status of overwhelmingly settled scientific consensus.

Vladtheimp

Thank you for sharing. I leave you with these thoughts:

1. Since 1998, more than 31,000 American scientists from diverse climate-related disciplines, including more than 9,000 with Ph.D.s, have signed a public petition announcing their belief that “…there is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate.” Included are atmospheric physicists, botanists, geologists, oceanographers, and meteorologists. http://www.forbes.com/sites/larr... plus, see link therein to Petition Project.

2. Europe, Facing Economic Pain, May Ease Climate Rules http://www.nytimes.com/2014/01/2... (Japan has already backed off from cutting greenhouse emissions)

Lanivan

No, No - please! You are much too gracious, too kind....Allow me to leave you with the following. Age before beauty and all that.....

U.N. Says Lag in Confronting Climate Woes Will Be Costly. http://www.nytimes.com/2014/01/1...

Vladtheimp

Oh, but I insist - my graciousness is but a drop in the Big Lake compared to yours, aged and decrepit as I may be. Let me add to the Global Warming wisdom from the U.N.

UN climate chief, Christiana Figueres, stated earlier this week that democracy is a poor political system for fighting global warming. She also said that communist China is instead the best model.

Air Pollution Linked to 1.2 Million Premature Deaths in China http://www.nytimes.com/2013/04/0...

OOPS -

Lanivan

Despite, or perhaps because of, your advancing years, you truly are a prince of a man, a gentleman, and a scholar, and I would love to share with you some of the Haribo Sugar-Free Gummy Bears that Barry Soetero has gifted me via the following website: http://www.amazon.com/Haribo-Gum...

I'm told by the New York Times that these are thought to be the panacea for future Climate Change skeptics in the face of overwhelming and settled scientific consensus.

Vladtheimp

Looked at the link - I was inordinately impressed - I was sure they would be suppositories. . . .

Lanivan

That can be arranged...

Vladtheimp

Backed into that one, didn't I?

Lanivan

...with remarkable depth perception...

Vladtheimp

Hah! What is the difference between a bureucrat brown-noser and a bureaucrat butt kisser?

Lanivan

Perhaps I 'assumed' too much...

Vladtheimp

Rather cheeky of you, eh wot?

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